Ingham County health officials say the recent illness that sickened 375 people at the Kellogg Center at Michigan State University was a norovirus.
The people had fallen ill after visiting the Kellogg Center during the third week of February.
People had complained of nausea, vomiting and diarrhea after attending events at the center and eating at the restaurant in the building.
County health officials say norovirus often points to hygiene and people coming to work sick.
Ingham County Health Officer Linda Vail says they had submitted seven samples to the state lab and all seven came back positive for norovirus.
She says norovirus is not uncommon, although the 375 cases is considered a large number.
Norovirus is often seen on cruise ships because it’s so contagious.
Vail also says often people who stay home sick return to work as soon as symptoms go away, but she says they should stay away from work for 72 hours after the symptoms subside.